Cardinality
The number of distinct values in a column. A country column has low cardinality; an email column has high cardinality.
Unexpected cardinality is one of the fastest signs of trouble. A status column with forty distinct values is not really a status column yet.
Where it comes up
- Inconsistent category labelsA column meant to hold a few fixed values holds many spellings of them.
See also
- Data profilingExamining a dataset to describe what is actually in it: types, ranges, distinct values, blanks, and patterns, column by column.
- Canonical valueThe one agreed spelling for a thing that can be written several ways, such as VA for Virginia, virginia, and Va.